(Oct 2) An international team of scientists has discovered a new source of gamma rays in the Universe. The study – published on the latest issue of Science – also has an Italian touch. Steven Shore, professor of astrophysics at the University of Pisa, has in fact collaborated to the research. Not only that. Along with Shore, partners of the study have been C-C. Cheung (Naval Research Labs., Washington DC), Jean Pierre (Institut de Recherche en Astrophysique et Planetologie, Toulouse France) and researchers from the Pisa section of the National Institute of Nuclear Physics. Gamma rays are a highly energetic radiation emitted during some of the most violent cosmic phenomena we know, but the observation of four novae, ie short stellar eruptions, carried out from 2010 to 2013 with the Fermi’s Large Area Telescope (LAT) has unexpectedly revealed that these events can produce gamma rays. “Before First observations with the LAT – said Shore – no one suspected these explosions, which are very common in the Universe, were able to produce gamma rays, usually associated with much more powerful cosmic explosions.” The hypothesis of the scientists is that the explosion of a nova creates various types of shock waves that expand themselves into space at slightly different speeds. The faster shocks may interact with the slow ones, accelerating the particles causing them to near the speed of light: these particles, ultimately, produce gamma rays. (red)
